After the initial checkout and commissioning, the communications experiments will examine the operational paradigm-shift of using the flexibility offered by SDR for space communications and navigation. Experiments will be conducted using the capabilities of the radio such as communications and navigation waveforms and applications. These investigations will use the frequency bands S-band and Ka-band (for TDRSS and ground), and L-band (for GPS). GPS reception will focus initially on the L1 signals and future L2 and L5 signals during the operations stage as they become available. For all bands, parameters such as availability, integrity, and performance will be evaluated. Networking capability is envisioned as part of the payload design. Ka-band experiments will include high rate communications, tracking, and pointing and channel characterization.
The SCaN Testbed is intended to be reconfigured from the ground with new software (avionics and SDRs) and firmware (SDRs only). Applications and waveform parameters such as forward error correction codes (e.g., low density parity check, block codes, Reed Solomon), adaptive power control, signal (pre)distortion (e.g., filtering), acquisition, and timing signals/parameters will be varied. SDR assessments will include Single Event Upset (SEU) fault mitigation and software reliability studies. The radios and waveforms will be compliant with the STRS architecture. The lessons learned from utilizing STRS will be the basis for updating the standard in the future; likewise, updated architecture implementations can be investigated.
Some experiments may involve modifying SDR waveforms or payload controller applications.
These new applications and/or waveforms, once verified on the ground, will require reliable file transfer to the target elements of the SCaN Testbed on-board system. Once installed, a sequence of pre-defined events will demonstrate the new capabilities.
CoNNeCT experiments will fall into five general categories:
advancing STRS technology
advancing SDR technology
advanced communication concepts
on-orbit networking technology
next generation navigation techniques
SCaN Testbed performance data will be collected and assessed over the life of the project. Comparisons will be made with archived ground unit verification and previous on-orbit performance to assess overall system health, determine sustaining engineering priorities, assist with anomaly resolution, and support experiment operations.